Another Overheating Problem--SOLVED!

We got it fixed and it is almost a comedy of "You got to be kidding me"

The heads and the intake were put on correctly, BUT with the small increase of CR due to the heads being done it appears that it was enough to push the cooling system over the edge.

We put it back with a new NAPA 190 degree thermostat and it would slowly over heat.

I thought, lets try a 180 to see what happens, well the same thing happened.

This was probably due to 2 factors, a slight bit of debris in between the condenser and the radiator, now we are not talking much at all just a couple of leaves and what appears to have been a weak water pump.

This is where the real problems started.

I ordered a Edelbrock Victor water pump and a Mr Gasket 180 thermostat and installed them and the problem was even more pronounced.

At this point I think I was starting to see trees instead of the forest.


We pulled the radiator and inter cooler and cleaned them, we also cleaned the condenser with it still in the car.

By now the car was undrivable due to rapid overheating.

We came in this morning and took the thermostat out, reinstalled the water neck to check for flow and to see if maybe the lower hose was collapsing.

You expect for new parts to work, but sometimes they don't.

The Mr Gasket thermostat was partially working when we installed it and then failed in the closed position.

We took all three of the NEW thermostats and put them in 200 degree water and the only one that would open fully was the 180 from NAPA that was the second one we installed.

Now we are getting some place.

We reinstalled this one and my overheating issues are gone.

In fact it has never ran as cool as it is now, 188 at 60 MPH with the oil temps stable at about 215.



There are a couple of lessons to be learned here, one is, some times you need to go back to square one and look at the figures that you have.

Everything was pointing to a low flow of coolant, but we had seen some coolant go through the radiator with the Mr Gasket thermostat before it failed completely.

Now the coolant temp sensor and the sender are reading with in a couple of degrees of each other.

I want to thank every one for there help on this.

Greg

 

Forgot to put in a link to the original thread.

http://forums.corvetteforum.com/show....php?t=2032531

 

Never over look faulty products, even new! Bought a brand new quality brand TV from a quality store. Got it home and it was DOA. Took it back and the replacement was also DOA! Third time was ok but PITA

From my experience, warranties are ok but failures seem to occur almost immediately. With corporations cutting cost qualty testing has gone out the window. If they had to start paying for the time and inconvience instead of just a replacement part things might improve.

 

Some one returned their old 'stat in a new box?

 

I've had stats fail in the closed position before, both on my 86 AND my 96.

I now use only the FAIL-SAFE version that, if it fails, does so in the OPEN position. AutoZone.

Jake

 

I also got my fail safe at the Zone. Nice piece.

 

I just got back from a long hard drive, it still runs hotter than I would like, but I think there are a couple of issues that need to be addressed.

It really needs a oil cooler and I think I need to somehow divert the the air from the blow off valve to the out side of the car instead of just below the coolant purge tank.

I am going to start another thread on oil coolers.

at 70MPH with a outside air temp of about 82 I saw almost 240 on the oil temp and 224 on the coolant temp.

Not to bad but still higher than I would like.

It seems like the capacity of the cooling system is marginal, even with the Griffin radiator and the Edlebrock water pump.

I can turn the heat on and the coolant temps will drop rapidly.

Maybe it is not all solved, but it is drivable now.

 

I did post that you should remove the rad cap and rev the engine and watch the coolant flow. Your stuck thermostats would have been found right away with that simple test. And I'll bet from now on you will test new thermostats with hot water before installing them. Also, there is more than one thread on a thermostat for C4's that has much less flow resistance when open (stewart/robertshaw). I installed a Stewart components water pump and realized much better cooling and Stewart claims higher flow than Edelbrock! I just looked on www.stewartcomponents.com site and they have stage 1, 2, 3, 4 water pumps for Chevy engines, I'd recommend you take a look at their water pumps and thermostats!

 

We were seeing flow at one point before the t-stat failed.

I may get one of the Stewart t-stats.

Are you saying that there have been problems with the Edlebrock water pump, or just that the Stewart is a better pump?

 

If your car is dependent on the heater water to cool it, it is not solved.
1. Make sure you burp the radiator when cold, and check the reservoir hose isn't cracked allowing the vacuum to escape when the system is cooling and drawing the water back into the radiator.
2. make sure the anti-freeze mixture isn't over 50-50. too high of coolant ratio will hinder cooling.
3. make sure the radiator cap is fresh, and not bleeding off pressure to your reservoir when you shut the car off. The higher temps exacerbate a pressure relief valve seal leak.
I drilled a hole in the heater valve, and I ty-wrap the heater valve in the off position so that when starting up a car in the summer after sitting in the blazing sun, I don't get a shot of heater before the vacuum moves all the valves. When it's 118 outside, you want all the A/C you can get!!!

 

It was almost 85 here today, it runs cooler that it ever has since I put the blower on.

Remember I have a large intercooler in front of the radiator, a sixty over motor and the heads have been cut at least three times since I have had the car and it is supercharged.

I do agree that it runs hotter than I would like, but I am happy with the fact that I can at least drive it now.

When you say burp when cold, not sure what you mean by that?
I have always ran it until it was hot enough to open the t-stat and bleed it at the small bypass hose at the back top of the intake, which looks like the highest point in the cooling system.
I then hold the RPM up at about 1700 and fill it as much as I can.

I am running 70% distilled water 30% coolant plus water wetter.

The hoses have been replaced.
The cap is good, it blows off at about 18 pounds and it is not making coolant in the purge tank.

The heater mod sounds good.

I like it hot, but 118, where you from death valley.

 

You might have a lot of air still in the system. A few drive cycles will bring it up, even when it don't burp it up.

Still that's not likely to keep the temps where you said they were this time.

But, what are the in and out radiator line temps now???

And can you shim the intercooler further from the radiator? What kinda' space you got in there now?

 

I have no idea what the in and out temps are now, but I got my IR temp gun in the car.

So am I not doing the fill correctly?

 

You probably are, but still some air don't cooperate much.

How much clearance do you have in the radiator / intercooler?

 

I never have measured it, but I would say a couple of inches.
Part of the problem is the huge scoop that directs the air flow up through the intercooler.

I have been thinking about going with one of Blowerworks meth systems and delete the intercooler.

 

Wow,hard to believe so many stats were bad...but glad ya found the problem.


Also,I got good advice years ago,for anyone,if one can,fill up the engine with as much coolant through the intake manifold or T stat until you cant out anymore.Then top off the rad.

Squeezing the hoses a few times will also help push air out of the system before closing it all back up.Youll see the coolant rise at the stat or cap area,then it will burp a bit on its own and go back down some more,to top off.Not a big difference but makes it much easier to pack the system.

This is more so if someone flushed the block,its low on coolant due to pump change,or one installed a new engine,but never hurts to make sure there is enough in there.

Otherwise,the temp guage will sometimes peg until the stat opens,before allowing the coolant to circulate and cool the engine off.

 

I think I would have saved myself a lot of grief if I had not decided to replace the T-stat when I did the head gaskets.

Ya got just as big a chance getting a bad part the first time as you do the tenth time.

Last week we went through six rotors from a dealer before we found 2 that were with in runout, and they were old ones.

They just made it in after indexing them.
You just never know.

 

well said, i think that many cooling system issues fall back to something that accidently got overlooked in the troubleshooting process. my heat problem a few months back was from not properly cleaning the fins. i shot some air and water in and called it good. went elsewhere when the whole time the radiator needed a pressure washing and 100+ psi behind the fins blowing all the years worth of crap out. did that and the temps fell..eventually bought a new unit for $99 from corvette recycling and the car runs between 80 and 95 on #16 of the climate control depending on how hot it is outside.

 

Bingo, We checked every thing, we just did not check everything after every change, new part so that has to be good.
Ya, that bit me in the ***.
I knew it had to be something that we had overlooked, something simple, I just could not believe that 2 pro wrenches with damn near 70 years between them could have put a set of head gaskets on upside down.

BUT, I had a guy ask me when I was looking for work once about come backs.
I told him that I did not have any come backs, he raised a eye brow and I told him that when I screwed up they did not come back they had to be towed back.

He did not think I was funny, I don't think he worked on many cars.


Greg

 

Stewart components makes the claim that their waterpumps deliver more flow rate than Edelbrock.